Fix compression threshold max limit from 4000 to 8000

- Updated hardcoded max limit in CompressThreshold input to match the 8000 token configuration
- Resolves issue where UI was limiting users to 4000 tokens despite backend supporting 8000
- Now allows users to set compression thresholds up to the full 8000 token limit

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/components/model-config.tsx

@@ -218,7 +218,7 @@ export function ModelConfigList(props: {
           aria-label={Locale.Settings.CompressThreshold.Title}
           type="number"
           min={500}
-          max={4000}
+          max={8000}
           value={props.modelConfig.compressMessageLengthThreshold}
           onChange={(e) =>
             props.updateConfig(